Improvement in steam-engine valve-gear



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THOMAS DYSON AND GEORGE SMITH, OF NEW YORK-N. Y.

Letters Patent No. 97,064, dated November 23, 1869; antedatcll Novemberl), 1865i.

The Schedule referred to in these Letters Patent and inaking part of the same.

l To all whom it may concern Be it known that we, THOMAS DYSON and GEORGE SMITH, of the city, county, and Stateof New York, have invented a new and improved Adjustable Valve- Gear for Steani-E11gines; and that the following description` taken in connection with the accompanying drawings, hereinafter referred to, forms a full and exact specification ofthe sanie, wherein we have set forth the nature and principles of our said improvement, by which our invention may be distinguished from all others of a similar class, together with such parts as we claim, and desire to have secured to usby `Letters Patent.

The object of this invention is to so construct the valves of steam-engines, more particularly engines wherein the piston is compelled to travel at great speed, and with short stroke, such as pumping and blowing-engines, 85e., that, for engines ofV this class, the ordinary 'way of opening and closing valves, by means of an eccentric, is unsatisfactory, and productive of loss of power, inasmuch as the eccentric, by its.- operation, begins to open thevvalves before the piston has reached the end of its stroke, and, in many instances, actually prevents the piston from completing its stroke, while in vothers the steam admitted before the completion of the stroke oiers serions opposition and work upon the engine to overcome the unnecessaryappliances in the same connection.

In the accompanying drawings, forming part of this specification- .Figure 1 represents a plan or top view of our inveution;

Figure 2, a longitudinal section of the same, taken in the plane of the line x c; and

Figure 3, a detached view of starting-apparatus.

.Similar letters of reference indicate corresponding parts in the several drawings.

To enable lothers skilled in the art to make and use our invention, we will'proceed to describe it fully and particularly.

A represents a cylinder, of cast-iron, which may be of any size desired.

B B are the cyliiider-hezuls, upon the upper side of which, and in line with the central axis ofthe cylinder, are cast supplement-ary cylinders a al', into which are properly fitted, with packing, the pistonsb b.

On to these pistons are attached the piston-rods e c', one end of which passes through the cylinder-head B, and projects into the cylinder A, at or near its upper 'inner surface, and the other ends of which project through the s'tutling-boxes d d'.

C represents the steam-chest, cast or ttedon to the cylinder A in the ordinary way.

Into this steam-chest are iitted the slide or doubl valve D and the supplementary slide-valve E.

When the piston H'has nearly reached the end 'ot itsstroke, (and before steam for the return-stroke has been admitted,) it comes in contact with the projecting end of the piston-rod c, driving it back, and opening the steam-channel t", and admitting steam into the supplementary cylinder a.. The steam thus admitted forces the supplementary piston l) to the end of the cylinder c, the piston b forcing with it, in its backward movement, the outward part of the piston-rod c.

To the outer end of the piston-rod c is fastened-the rigid connection L, by means of which the piston-rod c and valve-rod m are connected securely together, so that. when thepiston b, by its operation, moves the piston-rod c,it mustnecessarily move, at the same time, the valve-rod m, which, in turn, by its sliding or reciprocating movement; moves the valve D from right to left at each stroke; and, at the'same time, by bringing the toes 4n n alternately in contact with the toe p on the supplemehtary valve-rod o, the supplementary valve E is moved so as to admit orexhaust steam from the channels t' t.

The supplementary valve E is so arranged and connected as that, when steam is flowing into one supplementary cylinder, it is, at the same. time, being exhausted from the other.

The slide-valve D and supplementary valve E may l be adjusted to admit or exhaust steam to and from the cylinder A, or the supplementary cylinders a a', at any part of the stroke that may be desired, the same as in the ordina-ry cnt-ols, by simply shifting the toes n and p on their respective valve-rods. This is done by securing the toes with set-screws, which admit ofl being tightened or loosened, at pleasure.

Hitherto, engines of the blower or pumping 'class have been started by merely turning on the steam,-

and much ditticulty has been experienced, for, if the engine, at the moment of starting, happened to be at its dead-point, or, as is commonly termed, on its centre, it became necessary to move the valve by turning the ily-wheel; o1', if the engine were not on its centre, it might have a reverse motion, instead of a forward one, just as the valve happened to be placed for admitting steam on one side ofthe piston or the other. To obviate this diiliculty, we have invented of the valve-rod m, is a projection, so that, when the vWheel is moved tothe right or left, the fork presses on the right or left side of the projection, and thus forces the valve in the desired direction, whether for going ahead or reversing.

We are aware that valve-gears similar to our invention have before been invented,particularly/that of A. S. Cameron, patented October '3, 1865; but, while we disclaim anything contained iu his invention, we' desire to show that ours is not only dissimilar, but far more useful and effectual. In Oamerons invention, the valves are kept in place by the operation of springs; and, besides, hev uses no supplementary valve.; and, again, his supplementary piston has got to move a distance equal to its width before the full volume of steam is admitted, Oamerons supplementary valves acting as puppet-valves only, and ours acting more in the nature Witnesses:

FRANK HUDNER, GEO. E. TUTHILL. 

